1. Field of the Invention
The present invention relates generally to the fields of microbiology, immunology and pathology. More particularly, it concerns the development of particular monoclonal antibodies for use in the diagnosis and therapy of disease caused by Sarcocystis neurona infections.
2. Description of Related Art
Equine protozoal myeloencephalitis (EPM) is a widespread neurological disease in horses. Similar syndromes have been recognized in other species, such as marine mammals. It is progressive and in advanced stages, the horse will suffer from spinal cord and brain stem damage resulting in ataxia of the limbs and other signs of muscular incoordination, loss of response to certain sensory stimuli and muscle atrophy. In severe cases of recurrent neurological signs that do not respond to therapy, horses must be euthanized, which is very costly to owners.
Most cases of EPM are caused by a protozoan parasite, Sarcocystis neurona. This organism has been identified in other species and has been associated with encephalitis as well. The horse is thought to become infected with this parasite by ingestion of sporocysts shed by the opossum (Didelphis virginiana) or closely related species that are found in the Americas. This would suggest that horses shipped to other parts of the world could develop EPM later; therefore, EPM is not just a disease found in the Americas.
To date, there has been only one group—the inventors—that have disclosed a monoclonal antibody directed Sarcocystis neurona. Marsh et al. (2000). However, this report did not disclose the target for the antibody or how it was made. In addition, the antibody failed to react with certain strains of S. neurona, suggesting limited suitability for use in diagnostic screens. Thus, there clearly remains a need to identify additional antibodies that can be used in both diagnosis and therapy of S. neurona disease.